Gelatin-glycine is a known product, marketed for example under the Trade name Quick Moist®, comprising a mixture of gelatin and glycine in a proportion from 2:1 to 3:1 parts by weight.
The skin hydration effect of orally administered Gelatin-glycine is reported in the prior art for instance in EP-A-197898 (P. Morganti). Also the activity of Gelatin-glycine for concomitant topical and oral administration in increasing skin surface lipids, decreasing free radicals in blood and decreasing lipid peroxides is reported in literature: P. Morganti et al.: Cosmetic & Toiletries Magazine, Vol. 115, No. 9, September 2000.
Other works of the same authors have recently shown that antioxidant carotenoids given as diet supplements or in a topical formulation produce a significant photo protective activity, characterized by decreasing blood free radicals and lipid peroxides and accompanied by skin hydration and skin lipid improvement. See P. Morganti et al.: International Journal of Cosmetic Science, Vol. 24, pp. 331–339, 2002.
Although the results reported in the prior art prove already promising, they show that the increase of gelatin-glycine effect by increasing treatment time and amounts tends to a steady-state in which no further significant improvement can be observed. For instance it is reported by Morganti et al. in Journal of Applied Cosmetology, Vol. 7, 1989 pp. 103–109, that augmenting the oral administration of gelatin-glycine from 4 to 6 or even 8 pills a day does not cause any significant augmentation in skin hydration or reduction in superficial facial lines. In the same way, it is observed in Cosmetics & Toiletries, Vol. 103, April 1988, pp. 77–80, that the values of skin hydration recorded after 60 days treatment with gelatin-glycine do not significantly differ from those obtained after 30 days treatment.
For this reason, there remains the need for more efficient active principles exhibiting an enhanced activity and still capable of causing a rising effect over the long terms.